Britannica Sources used in this answer

Why is complementary DNA easier to study in the laboratory than RNA?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Diagram illustrating the process of retrovirus infection and reverse transcription, showing a retrovirus entering a host cell, releasing viral RNA, reverse transcriptase converting RNA to DNA, integration into the host genome, transcription of new viral RNA, assembly of new virions, and budding from the cell. — Reverse transcriptase After a retrovirus infects a cell, an enzyme known as reverse transcriptase converts viral RNA into proviral DNA in the cytoplasm. Proviral DNA then enters the nucleus, where it is incorporated into the host cell's DNA.

Complementary DNA (cDNA) is easier to study in the laboratory than RNA primarily because RNA is a fragile molecule that is difficult to work with.1

The chemical structure of RNA contributes significantly to this instability. Specifically, the presence of a 2′-hydroxyl group on the ribose ring makes RNA susceptible to cleavage when exposed to alkali, which breaks the phosphodiester bonds. Additionally, while DNA is typically a stable, double-stranded molecule, RNA is usually single-stranded and flexible, often forming complex, compact three-dimensional structures through internal base pairing that can complicate experimental analysis.2

Because of these challenges, researchers use the enzyme reverse transcriptase to synthesize a more stable DNA copy—known as cDNA—from RNA templates. This cDNA can then be reliably amplified using polymerase chain reaction and utilized for various downstream laboratory applications, such as the creation of cDNA libraries.13